Alternatives to the standard method of diagnosing sleep apnea (SA) are becoming increasingly popular due to the expense and/or. In some cases, the limited availability of polysomnography (PSG). The most common diagnostic alternatives have been clinical prediction rules and portable monitoring. Most portable monitors record one or more signals such as oxygen saturation, heart rate, airflow, or ribcage and abdominal movements. To date, most published studies of these monitors have had serious methodologic problems that have limited the acceptance of this technology. We have developed a two-step diagnostic approach for SA based on a clinical prediction rule and the results from a simple, but reliable and accurate, portable monitor that records oxygen saturation, snoring, and body position. The preliminary results indicate that such a strategy is very useful in a population of outpatients suspected of having SA and would preclude the need for PSG to investigate for this possibility in the majority of patients. However, before portable monitoring becomes widely adopted, each system should be more thoroughly tested, and increased attention should be directed at the design of the study so that the results are more generalizeable to other sleep clinic populations.